Method of sliting and inserting wire in a plug



July 2, 1957 D. D. HUYETT 2,797,473

METHOD OF SLITTING AND INSERTING WIRE IN A PLUG Filed may 5, 1954 3 Sheets-Sheet 1 JTTORNEYJ' 2,797,473 METHOD- OF SLITTING AND INSERTING WIREIN A PLUG Filed May :5, 1954 D. D. HUYETT July 2, 1957 3 Sheets-Sheet 2 ATTORNEY July 2, 1957 D. D. HUYETT 2,797,473

METHOD OF SLITTING AND INSERTING WIRE IN A PLUG Filed May 3, 1954 3 Sheets-Sheet 3 2 5 7 M5 INVENTOR- EM /00 M7 4 BY W /05 4 M2 ATTORNEYS "METHOD F SLITTING AND 'INSERTING WIRE IN -A PLUG Daniel D. Huyett, Wilmington, Del, assignor to Atlas [Powder 'CompannWilmingtOn, DeL, a corporation of Delaware Application May 3, 1954, Serial No; 427,064

4 Claims. (Cl. 29--450) The present invention relates to new and useful improvements in wire insertion'methods and 'r'noreparticu- 'larly to new-and useful improvements in methods for J providing a longitudinal slit in eachof a plurality of rub- 'application'Serial No.i249,298, filed October 2, 1951. "Prior to thepresent invention and as disclosed in my U. S. Patent'No. 2,657,454, the customary procedure followed in the insertion of pairs of wires into plugs was to position a plurality of solid plugs formed of a resilient material, such as rubber, into a plug holder and then "cause pairs of spaced, ax'ial aligned perforating points or i needles to pierce the plugs in advance of a complementary pair of sleeve-like elements or tubes moving with said needlesand carried thereby, the needles functioning to form pilot openings in the plugs for reception of the tubes. The needles are then withdrawn leaving the tubes through the plugs for reception of a pair of wires. The

"tubes are then withdrawn leaving the plugs'in fir'rn gripping enclosure of the wires. I This method possesses one principal disadvantage in that the solid plug material between the pair of'needles forces the points of the needles outwardly causing 'them to diverge away from each other so that the needles rub against the inner surface of the tubes with'result'ing excessive wear of the parts. "Spreading of the needles also causes the'tubes to spread outwardly resulting in'wear on the exterior of the tube ends causing them to become sharp, deformed, and split or broken so that they 'cut the plug material. In addition, the spreading of the needles causes the needlepoints to bear hard on the tapered or funneled inlets to the plug holding jaws causing them 'tobecome worn and exposethe tubeends so'thatthe latter constitute obstructions to proper insertion of the wires into the tubes.

With the foregoing in mind, theprincipal object of the present invention is to provide'novel 'apparatusfan'd methods for simultaneously slitting-aplurality of're'silie'nt plugs prior to insertion of a corresponding plurality'of pairs of wires through the plugs.

Another object of the present inventionis topiovide novel apparatus and methods of the stated character which-greatlyimprove upon prior wire insertion practice an'd prevent excessive wear on the wire insertion 'apparatus.

'A further object of the present invention isto provide novel apparatus and methodsfor forming along'itudinal "slit-in a rubber 'plug and then inserting "a" pair of needles through-the slit-indie plug followed by apair of tubes A preparatory to p'os'itioninga pairof wires "in t'he rubber plugs.

United States Patent C A further object of the present invention is to provide novel apparatus and methods which combine the plug slitting operation with the transfer of the plugs from a first holder to a second holder.

A still further object of the present inventionis to 7 provide novel apparatus and methods having the features taneously;

Fig. 2 is a fragmentarytransverse sectional view taken on line 2-2 'ofFig. 1, illustrating the mechanism for actuating the plug slitters;

Fig. 3 is an enlarged fragmentary transverse sectional view taken on line 33 of Fig. 1, illustrating the plug transfer and slitting mechanism;

Fig. 4 is a front elevational view partially in section of'mechanism illustrated in Fig. 3;

Fig. 5 is a sectional plan view taken on line 5-5, Fig.1 'illus tratingthe means for positioning the plugs and plug holders in the 'slitt'ingmachine;

\ Fig. 6 is a'tra'nsverse sectional view taken on line 6-"6, Fig/'5 illustrating the latch means formaintaining the plug holders in the slitting machine;

' inserted into the slitting machine;

Fig( 8 is a perspective view of a preformed plug closure 'having a pair of wires inserted therethrough according to the process of the'present invention;

Fig. 8a is a side elevational view partially in section of an electric blasting cap incorporating the preformed plug closure assembly shown in Fig. 8.

Fig. 9 is an enlarged fragmentary sectional view illustrating the position of the plugs-and various other operating parts of thepresentinvention immediately. prior 'to i the slitting operation;

Fig. 10 is a fragmentary sectional view similar to Fig. 9 at the-end of the slitting operation;

Fig. 11- is -a sectional plan view taken on line 11- 11, Fig. 10 illustrating the position of a plug in a plug holder "with the slittingblade extending therethrough;

Fig. 12 is-afragmentary"sectional view of'the cloverleafplugholdtar with a plug 'positicne'd therein;

. -Figs. l3 'to 18,iriclus'ive,- are" enlarged fragmentary sectional viewsillustrating the successive steps in theinser- "t'ion'of the' wire's through the slit plugs of the presentinvent'ion;

'Fig. l9 is a'sche'rnatic wiring diagram illustrating the control mechanisrn for the slitting machine of thepresent invention; and I 19a is a sectional "View taken on line "19 19, "Figfl6.

Referringmow to the drawingsand particularly Fig. 1 thereof, o'ne form of slitting machine'made'in accord- '*ance with the present invention comprises generallya frame 20 and "a "fiat horizontal table 21 projecting outwardly at oppositesides of the frame. The table 21 supports a pair of plug holders 22'and 23 in proper position relativeto"theoperating mechanism of the slitting machine, and resilient plugs 24 formed of rubber or like 'material,"are transferred from the first holder "22 to the 3 second holder 23 and are slit during operation of the slitting machine.

The two plug holders 22 and 23 are illustrated in Figs. 3 and 7 of the drawings. The plug holder 22 has a plurality of openings 25 extending therethrough which are adapted to receive the resilient plugs 24. Each opening 25 is provided with a shoulder 26 to provide a plug receiving portion of greater length and greater diameter than the plug so that the plug may be readily inserted into the openings of the holder 22. The plug holder 23 has a plurality of clover-leaf shaped openings 27 extending therethrough corresponding to the number of openings 25 in the holder 22. The clover-leaf openings 2'7 are of a diameter slightly less than the diameter of the resilient plugs 24 so that the plugs 24 must be forced into the openings 27 and after the plugs are in the openings 27 they are prevented from moving relative to the openings by the frictional engagement of the plugs with the side walls of the openings 27. Guide blocks 28, 28 are fixedly secured to the opposite rearward corners of the plug holder 22 and extend upwardly therefrom adjacent the front and side surfaces of the plug holder 22, for example, as illustrated in Fig. 7. These guide members 28, 28 engage the corners of the plug holder 23 and properly position the plug holder 23 relative to the plug holder 22 with the openings 27 and 25, respectively, in axial alignment with one another.

After the holders 22 and 23 are placed together with a plurality of resilient plugs 24 in the openings 25 of the holder 22, the two holders are inserted into the slit- 1 ting machine on top of the table 21 in the relation shown in Fig. 3. With reference to Fig. 5, positioning blocks 31, 31 are bolted to opposite ends of the table 21, for example, as indicated at 32, and engage the outer side edges tioning blocks 33, 33 for example by means of bolts as indicated at 36, and extends forwardly from the positioning blocks 33, 33 to overlie the upper surface of the upper plug holder 23 with the slots 35 in alignment with the plug holder openings 27. By this construction when the two plug holders 22 and 23 are placed on the table 21 of the slitting machine in engagement with the pairs of positioning blocks 31 and 33 the plug holders 22 and 23 will be in the proper position relative to the slitting machine.

In accordance with the present invention means are provided to secure the plug holders 22 and 23 in position on the slitting machine and prevent operation of the slitting machine when the plug holders are not properly positioned therein. To this end, a pair of latches 37, 37 are pivotally mounted adjacent opposite sides of the stripper plate 34, for example, as indicated at 38, 38 and extend forwardly beyond the forward surface of the stripper plate, as shown in Figs. 3 and 6. During insertion of the plug holders 22 and 23 into the slitting machine the rear edge of the upper plug holder 23 engages cam surfaces 39, 39 on the forward ends of the latches 37, 37 and pivots the latches upwardly about their pivot points. When the plug holders 22 and 23 reach their rearward limit position in the slitting machine against the positioning blocks 33, 33 the latches 37, 37 engage the forward surface of the upper plug holder 23 and maintain the two plug holders 22 and 23 in position against the blocks 33, 33. When the latches 37, 37 are in this position in engagement with the forward surface of the upper plug holder 23, the rear ends of the latches engage and close a pair of series connected control 4 switches 41 and 42 which are also in series with a start switch 43.

When the start switch 43 and switches 41 and 42 are closed, the machine is placed in operation. The plugs 24 are first transferred from the openings 25 in the plug holder 22 to the openings 27 in the plug holder 23 where they are slit longitudinally. More particularly, upon actuation of the start switch 43 when the two control switches 41 and 42 are closed, hydraulic fiuid, such as air under pressure, is admitted to the lower end of a hydraulic cylinder 44. With reference to Fig. l, the cylinder 44 is secured to the frame 20 of the machine and has the upper end of its piston rod 45 connected to a cross head 46. The cross head 46 is mounted in slides 47, 47 secured to the frame 29 and may be moved between upper and lower limit positions by means of the hydraulic cylinder 44. When hydraulic fluid under pressure is admitted to the bottom end of the cylinder 44 the cross head 46 is moved to its upper limit position and conversely, when the hydraulic pressure is released from the lower end of the cylinder 44, the cross head 46 is moved to its lower limit position.

Extending transversely of the cross head 46 at the upper end thereof is a plunger support 48 which carries a plurality of slotted plungers 49, for example, as illustrated in Figs. 3 and 4 corresponding to the number of openings in the plug holders 22 and 23. In the lower limit position of the cross head 46 the upper ends of the plungers 49 are positioned interiorly of openings 51, in table 21, and the openings 51, in turn, register with the openings 25 in the lower plug holder 22. During movement of the cross head 46 to its upper limit position the plungers 49 are moved upwardly into engagement with the bottoms of the plugs 24 in the lower plug holder 22 and force the plugs 24 upwardly into the openings 27 of the upper plug holder 23, for example, as illustrated in Fig. 9 of the drawings. As previously described the openings 27 of the upper plug holder 23 are of clover-leaf shape, as shown in Fig. ll, and frictionally engage the side walls of the plugs 24 to prevent relative movement of the plugs 24- with respect to the plug holder 23.

When the cross head 46 reaches its upper limit position, a switch actuating member 52 carried by one side of the cross head, as illustrated in Fig. 1, engages and closes a switch 53 secured to the slide 47. This, in turn, causes hydraulic fluid under pressure to be admitted to a hydraulic cylinder 54 which has its lower end. pivotally secured to a bracket 55 extending outwardly from the rear of the frame 20, as illustrated in Fig. 2. The forward end of the piston rod 56 of the hydraulic cylinder 54 is pivotally secured, as illustrated at 57, to one end of a rocker arm 58. The opposite end of the rocker arm 58 is fixedly secured to a shaft 59 extending transversely of the slitting machine so that when hydraulic fluid under pressure is admitted to the hydraulic cylinder 54, the shaft 59 is caused to rotate in the clockwise direction relative to Fig. 2, and when the hydraulic pressure is released the shaft 59 is caused to rotate in the counterclockwise direction. A pair of pinions 61., 61 are secured to the shaft 59 in engagement with racks 62, 62. The racks 62, 62, in turn, are carried by a cross head 63 extending transversely of the slitting machine and slidably mounted in slides 64, 64 secured to the frame 20 for vertical movement between upper and lower limit positions.

With reference to Figs. 3 and 4, a plurality of slots 65 are provided in the front face of cross head 63 and are adapted to receive a corresponding plurality of knives 66. Each knife 66 is secured in a slot 65 by means of an adjustable locking bolt 67 passing through a guard member 68 secured to the front surface of the cross head and by loosening the adjusting bolts 67, the knives 66 may be adjusted vertically relative to the cross head 63. In the upper limit position of the cross head 63 the lower ends of the knives 66 terminate in the slots 35 of hydraulic fluid to the hydraulic cylinder 54 .the shaft 59 is caused to rotate in the clockwisedirection relative to Fig, 2 and the knives 66. are actuated downwardlyfinto engagement with the plugs 24 secured in :the openings 27 of the upper plug holder 23. The end. portions of. the knives 66 are passed completely through, the plugs 24 to a position within the sl'otsinthe upper ends ofrthe .slottedplungers 49, for example,1as illustratedinFig.

of the drawings. thereby, providing atransverse 'slitlongitudinally through the plugs 24. his to be noted particularly that the width. of the transverse slit formed by the knives 66 is substantially less than thediameter ofthe plug'24 so that the oppositeedgesof'the:slitnatrno point extend to the circumference of the plug'andI-the slit is entirely surrounded throughoutits length by the resilient material of ,theplug.

When the crosshead 63" reaches its lower limitposition a switch actuating memberr69 .secured to'the rear surface of the cross, head 63, engages and closes a switch 71 which releases the hydraulic pressure from the lower end of the hydraulic cylinder 44. causing the piston of the hydraulic cylinder44 to be: moved :toits lower limit position thereby lowering 'the crosshead 46' and moving the-plungers'49 to their'zlower limit position. 'As'the cross head 46 is lowered, the switch actuating member 52 carried by'tlre cross head 46 is disengaged from the switch 53y'thereby opening the switch 53. and permitting the hydraulic fluid to beexhausted from thelower end of the hydraulic cylinder 54. This permits the piston of I the hydraulic cylinder 54 to bemoved toits lower limit position thereby'rotating the shaft 59 inthe clockwise direction and elevating the knives.

During initialzupwardmovement of the knives 66 they carry with them the plugs24 thereon and the holder 23. This upward travel .of the plugs 24. and holder .23 at the start of the upward movement of the knives. 66 continues for avery short distance only untilthetop surface of the holder 23 engages the underface of the stripper plate 34 as shown in Fig. 10 of thedrawings. In this position of the holder. .23 the projections 34a on Y the underside of the stripper plate 34'are received within the openings 27 \of the holderv 23.and are engaged .by the top surface of the 'plugs 24 as shown. Tlhus, as

.upwardmovement of the knives 66 continuesvthe knives are withdrawn from the :plugs and :the latter are retained by the projections34a in a position centrally inthe holder openings 27 withclearance both above and below the plugs as illustrated in 'Fig. 1 12 of the *drawings.

This completesone cycle of. operation of the slitting machine-of the present inventionrand the latches .37,

assume-1at,the end of one complete cycle of operation .of {the slitting machine prior to tl1e;positioning.of ea;- pair of; plugholders on the slitting machine table.

As a pairof plug holders is inserted into {thetslitting machine the switches 41 and 42 are closed and upon closing the start switch 43 a circuit is completed through the switches 41, 42 and 43 from a lead line 75 at one side of the line to the coil 76 of a relay 77 and then through a lead 78 to the 'other side of the line. This energizes the coil 76 and actu-ates the relay 77 to its upper limit position thereby completing a circuit through a first pair of contacts 79 andwa second pair of contacts 81. Upon completion of a circuit through the second pair of contacts 81, the coil 82 of a solenoid valve 83 vzis energized and the. valvesa83 is .moved to the right from the; position: shown thereby j permitting hydraulic fluid underwpressure. to .be admitted to. the lower end of the hydraulic cylinder 44. The circuit forthe coil '82'is from. therlearl 75:at one side: of the line through the lead line.84,';thei contacts 81, lead line 85 to the coil 82Iuand 1 its upper limit positionthe switch 53 is closed thereby completing a circuit to :the coil. 87 of. asolenoid-- valve :88: which in turnmoves'the solenoid v alve'ito the right :from theposition shown permitting hydraulicfiuid under pressureato'be admittedtothel-ower end of thehydraulic cylinder 54. :This causes'the piston of thegcylinder 54 11:0 be'moved to-its upper limit position-thereby forcing the knives downwardly. When-the cross'rhead 63 carry- :ing theknives reaches'its lower limit'position: the switch '71 is;closed thereby energizing a coil:-'91 of a relay-"92 actuating the relay: 92. upwardly to open the circuit through a pair 'of :contacts 93. The contacts 93 are in series withzthezfirst pair of contacts'79 .of the-relay '77 and theholding circuit forthe relay. coil 76 passes throu'ghthercontacts 79 and 93. When this holding :circuit :is-brokentby: energizing the relay 92uthe relay :coil76 .is deenergized thereby permitting the relay 77. to bermoved'fdownwar'dly breaking the circuit through lithe contacts-r81 for-.Ethesolenoid valve 83. The'solenoid 'walver83 .is::=thenrreturned to its off p'oSitiOnLpermitting 1air:*.to;beexh'austedwfromthe lower end of the hydraulic .cylinder 44'aand the"hydraulic cylinder 44 moves to .itSZr-lOWerfipOSitiOIi. During movement of the hydraulic cc'ylinderi44 toritsl'lower. limit position the switch53-is -:opened, :as'previouslydescribed, which de-cnergizes the end of the-hydraulic cylinder 5 4.

Thistpermitsithe knives166 to be retracted thereby com- "pleting-i'one .cycle of operation of the slitting machine.

If-ltiiSZ clesiredto'. stop'operation of the slitting machine .at any time during 'its cycle of'operationastop:switch =94"which isrin series with the above-mentioned. pairs of 45:

contactsv79iand-93 is opened causing the coil'76 of the cylinder '77 to ibe-t-det-energized as previously described,

1 thereby stopping operation of the slitting machine.

An'important feature of the present invention is'the method of inserting a plurality of pairs of Wires'100 I into a corresponding plurality of resilient plugs to. form 'a finished article, forexample, as illustrated in Fig. 8,

"consisting of a plug'having a pair-of wires inserted 'therethrough. Asdescribed previously, the plugs 24 are "first transferred to aclover-leaf plug holder 23 and main- -'-tained in the desired position in the clover-leaf plug holder by frictional engagement between the walls of the openings 27 in'the'plug holder and the outer surfaces -of the'plug. "After the plugs 24 aretransferred tothe "plug" holders 23, the-plugs are slit longitudinally, "for example, by means of the knives as shown in Fig.'l0. After "the 'plugsiare 'slit by the'knives the plug holder 231s positioned intermediate a'pair of guides101 and 1'02with'theslitin each'plug exten'dingin a predeter- 'mined position. .A' plura'lity of pairs ofi'needles 10 3, 103 are"mounted'adjacent"oneside of the plugflholder 23 for relative movement between forward and rearward limit positionsand in' the forward limit position thereof In addition, a pair of tubes 104, 104 is positioned coaxially with each pair of needles 103, 103 for relative longitudinal movement between forward and rearward limit positions. In order to retain the pairs of tubes 104, 104 in truly parallel relation as they pass through the slit in the plug, the tubes of each pair preferably are secured in fixed relation to each other by means of an intermediate connecting web 104a arranged as shown in Fig. 19a of the drawings and extending substantially the full length of the otherwise free or unsupported end portions of the tubes. The pair of wires 100, 100 is positioned at the opposite side of the plug holder from the needles and tubes in axial alignment with the needles and tubes and guide means 105 is provided to direct the wires 100 toward the plugs 24. A pair of needles, a pair of tubes and pair of wires are provided for each plug carried by the plug holder 23.

With reference to Figs. 13 to 18, inclusive, of the drawing, there is illustrated the various steps in the wire insertion method of the present invention. The needles and tubes 103 and 104, respectively, are in the position illustrated in Fig. 13 at the start of the insertion operation. In order to insert a pair of wires through a plug 24 the needles 103 are first forced toward their forward limit position wherein the points of the needles pass through the slit opening in the plug 24. After the needles 103, 103 have pierced the plug 24 the tubes 104, 104 are projected to their forward limit position and are forced through the slit in the plug 24. The needles are then withdrawn, for example, as shown in Fig. 15 of the drawings, and a pair of wires 100, 100 is inserted through the guide means 105 into the tubes 104, 104. This position is illustrated in Fig. 15 of the drawings. Upon further retraction of the needles and further insertion of the wires, the wires pass entirely through the plug, for example, as illustrated in Fig. 16 of the drawings, and the tubes 104, 104 are retracted from the slit opening in the plug. The needle insertion apparatus is now in the position illustrated in Fig. 17 of the drawings wherein the pair of wires is securely gripped by the plug, while the plug is still in the plug holder 23. The needles remain in the retracted position while the tubes 104, 104 are again forced toward their forward limit positions engaging the forward surface of the plug and forcing the plug out of the plug holder 23. This completes the slitting and insertion operation of the present invention and the plug holder 23 may be returned to the slitting machine to receive a subsequent supply of plugs to be slit.

From the foregoing it is apparent that the present in vention provides new and useful improvements in apparatus and methods for providing a longitudinal slit in each of a plurality of plugs and inserting a corresponding plurality of pairs of wires into the slit plugs which greatly improves upon prior wire insertion practice and prevents excessive wear on the wire insertion apparatus. In addition, it is apparent that the present invention provides novel slitting apparatus for slitting a plurality of plugs simultaneously to prepare the plugs for further wire insertion operations. I

While particular embodiments of the present invention have been illustrated and described herein, it is not intended to limit the invention to such a disclosure and changes and modifications'may be incorporated and embodied therein within the scope of thefollowing claims.

I claim:

1. The method of inserting a pair of wires through a plug of resilient material which comprises, slitting the plug axially thereof for a Width substantially less than the diameter of the plug, inserting a pair of spaced apart needles through the slit in said plug, inserting a pair of tubes through the slit in the plug with each tube coaxially circumscribing one of said needles, withdrawing the needles from the plug while retaining the tubes therein, inserting wires through said tubes, and withdrawing the tubes while retaining the wires through the plug thereby releasing the resilient material of the plug to cause same to engage about and grip the wires thereon.

A method of introducing a strand material through a solid resilient substance and securing the same therein, 'which comprises the steps of slitting the substance entirely therethrough in one direction for a Width substantially less than the dimension of the substance in the direction normal to the direction of slit, inserting a needle and a sleeve coaxially through the slit in said substance, said sleeve having an internal diameter not substantially greater than the maximum external diameter of the body of said needle, said insertion of said needle and sleeve expanding the substance at opposite sides of the slit and forming an opening through said substance of a diameter corresponding to the external diameter of said sleeve; withdrawing said needle from said sleeve where said sleeve is encompassed by said substance; inserting strand material axially into said sleeve where said sleeve is encompassed by said substance; and Withdrawing said sleeve from said substance while maintaining said strand material within said substance whereby said substance contracts about and grips said strand material.

3. A method of introducing a strand material through a solid resilient substance and securing the same therein, which comprises the steps of slitting the plug axially thereof for a width substantially less than the diameter of the plug, inserting a pair of spaced parallel needles lengthwise through the slit in said substance, inserting a sleeve coaxially of each needle through the slit in said substance, the sleeves having an internal diameter not substantially greater than the maximum external diameter of the body of said needles, the insertion of said needles and sleeves expanding the substance thereabout and forming laterally spaced openings through said substance each of a diam eter corresponding to the external diameter of said sleeves, withdrawing the needles from said sleeves while retaining the sleeves in and encompassed by said substance, with drawing said sleeves from the substance while maintaining the strand material therein and causing said substance to contract about and grip said strand material.

4. In the method of slitting plugs composed of a solid resilient substance, the steps which comprise frictionally supporting the plug at spaced points circumferentially thereof, supporting said plug at one end against actual displacement thereof, and slitting the plug in a direction axially inward from the opposite end thereof for a width transversely of the plug substantially less than the diameter thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,803,871 Sgritta May 5, 1931 1,863,389 Anderson June 14, 1932 2,289,677 Perelson July 14, 1942 2,340,419 Nawoj Feb. 1, 1944 2,497,921 Ballard Feb. 21, 1950 2,645,004 Dorner July 14, 1953 

